Cut sheets of paper for use in photocopiers, printers and like equipment are typically packaged in stacks containing from 100 to 800 sheets of paper, depending upon the type of paper being packaged and its purpose. A ream of paper normally contains 500 sheets, but as used herein a ream is intended to cover a stack of cut sheets regardless of the number of sheets in the stack. The packages, or reams, normally are individually wrapped or covered with a ream wrap material and the wrapped reams usually are packaged in a box or carton for shipment and storage. The ream wrap maintains the stack of sheets intact, protects the wrapped paper from physical damage and moisture pickup during shipping and storage, and also protects the paper during handling and storage at the point of sale and/or point of use. When the need arises for loading paper into a machine that uses the paper, the ream wrap is removed from one or more reams of paper and the paper is placed in the bin or other compartment of the machine for supplying paper to the machine during its operation.
Ream wrap typically comprises paper, or paper coated with a moisture resistant material or otherwise treated to obtain a desired property, or a poly film that may consist of a relatively heavy gauge monolayer film or a composite of two or more separate layers of lighter weight plastic films laminated together with an adhesive. The wrap is applied by placing a stack of cut sheets of paper on a sheet of ream wrap material that is then moved through a wrapping machine that folds the wrap about the stack and seals it to enclose the stack. The wrap normally is applied so that two long edges extend in the longitudinal direction of the stack and overlap at the midportion of the top of the stack. These overlapped edges can be heat sealed or adhesively attached together with glue, and in a finished package the longitudinal seam produced by these sealed together overlapped edges is on the bottom surface of the package. The longitudinally seamed wrap is then folded inwardly at the sides where it extends past the ends of the stack, followed by inwardly folding the material that extends past the ends of the stack at the top and bottom, defining two overlapping flaps. This inwardly folded material at the ends of the stack is adhesively attached or heat sealed together to secure the wrap about the ream of paper.
For instance, adhesive is normally used on paper wraps, and sometimes on poly wraps, to secure together the overlapped wrap material on the ends of a ream. Seals produced by adhesive are generally inferior in quality compared with heat seals, especially when used on poly wrap, since the adhesive can get on the cut sheets of paper and precise positioning and quantity of adhesive applied can be difficult to control.
In ream wrap that is heat sealed, the wrap comprises a heat sealable material, which can comprise a poly film or a coated paper or other heat sealable material that is capable of being fused together by the application of heat. The ends of the wrapped ream, where the wrap is inwardly folded and overlapped, are heat sealed by applying heat to fuse the material together. In conventional heat-sealing systems belts at each end of the wrapped reams convey the reams through a heating zone having one or more heat plates positioned at each side of the zone, and as the ream is conveyed through the heating zone the plates apply heat to the ends of the wrapped ream to fuse the wrap together where it overlaps at the ends. In conventional machines the plates apply heat to the entire end of the wrapped package, whereby the entire area of overlapped wrap material is fused and sealed together. This results in a strong attachment that is not likely to rupture during handling and storage, but it is also difficult to open.
It would be desirable, therefore, to have a ream wrap that has all the desirable properties of conventional ream wrap, including adequate strength to avoid bursting during handling and storage, but which is also easy to open.